Harbor Freight Tools Model 67980 - Manual (Page 13)

Installation and Connection
Video-Out Cable Connection
11
16B
3.5 Video-Out Cable Connection
Insert the video-out cable into the video-out port of the tool and the
other end of the cable into the video-in port of a TV. The LCD screen
will output a high quality real-time image.
16B
3.6 Earphone Connection
Connect an earphone with microphone (optional, not included) to the
earphone port of the tool. Speak into the microphone to record your
voice.